Since the appearance of the Princess Leia holographic message in the 1970's Star War movie, researchers have been exploring the feasibility of producing a real world prototype. Recently, similar excitement has been stirred up in the community with the “Three Dimensional (3-D) forensic chamber” in the television series “Bones”. The closest systems that have been built so far are the Cheoptic-360 and the Holography-360, which allows a Two Dimensional (2-D) object scene to be floated in mid-air and observed by viewers from the four sides. However, it is simply the projection of a 2-D planar image, and there is no depth or disparity information as in the original object scene. To create the 3-D illusion, the scene (or the object(s) in the scene) on each side is/are rotated continuously.
Generation of a floating image can be achieved with aerial projection. To generate a floating image, a real object is placed in an area which is generally not visible to the viewer. When illuminated, an image of the object is reflected by a beam-splitter and observable as a virtual image by the viewer, creating the impression of the object image floating in air. A background image, or a concave mirror, is sometimes added to enhance the effect. One of the significant disadvantages of this approach is the requirement of a real object.
Another method has been employed to remove the need of a real object, wherein a 2-D image of the real object is captured by a camera, and reproduced with certain display device such as a cathode ray tube (CRT) monitor, liquid crystal display (LCD) monitor, or an optical projector. The image produced by the display device is reflected by a beam-splitter and projected to the viewer as a virtual, floating image. Similarly, a background image or a concave mirror is sometimes used to provide the illusion of a 3-D effect.
The above methods and systems only provide viewers the ability to observe the floating image from a single direction. An existing product known as the “HoloCube 3D Projection Box” is based on similar principles. Recently, this has been extended to integrate two or more such aerial projection units, each projecting a floating image independently along a unique direction. The directions of projection are generally two or more of the following: front, left, right, back. An advantage of this approach is that viewers can observe the projected image from an aerial projection unit, as well as the environment behind the aerial projection unit. In this product, there is no background device or mirrors to block the sight of the viewer. Such concept has been adopted in the Cheoptic-360 system and the Holography-360 system. However, with these systems, the floating image lacks the 3-D information, such as the depth perception, and parallax is absent as the observers move their viewing positions with respect to the displayed image.
Some other conventional hologram display approaches include the foreground/background approach (e.g., as found in Dolgoff, U.S. Pat. No. 7,492,523, “Method for displaying a three-dimensional scene”), the multi-layer display (e.g., as found in Leung et al., U.S. Pat. No. 5,745,197, “Three-dimensional real-image volumetric display system and method”, Refai et al., U.S. Pat. No. 7,537,345, “Volumetric liquid crystal display for rendering a three-dimensional image”), and the spinning mirror (e.g., Jones et al., “Rendering for an Interactive 360° Light Field Display”, Siggraph, 2007).
These conventional hologram display approaches have a number of deficiencies. For instance, conventional holographic display systems that generate holographic images of a 3-D real scene require multiple optical signals from multiple optical cameras continuously capturing the respective views of the scene in order to generate recreate the scene as a holographic image. Such multi-camera arrangement can be expensive, complicated and tedious to undertake, and relatively inefficient. Also, holograms projected using conventional approaches lack depth perception and parallax information (e.g., disparity information).
Today, there is no efficient, economical, less complex way to capture visual information of a 3-D object scene. Further, currently there is no way to generate, maintain, or display disparity information of an original 3-D object scene. The above-described deficiencies of today's systems are merely intended to provide an overview of some of the problems of conventional systems, and are not intended to be exhaustive. Other problems with the state of the art and corresponding benefits of some of the various non-limiting embodiments may become further apparent upon review of the following detailed description.